From 81e1ae52a3cde6a2c21056ec53f91e790e7ac24b Mon Sep 17 00:00:00 2001
From: Pawan Rawal <pawan@dgraph.io>
Date: Mon, 26 Jun 2017 13:21:03 +1000
Subject: [PATCH] Write deletions to value log even if SyncWrite is set to
 false. Fix #72

---
 badger/kv_test.go | 33 +++++++++++++++++++++++++++++++++
 badger/value.go   |  2 +-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/badger/kv_test.go b/badger/kv_test.go
index 0af03605448..0fc56cfd007 100644
--- a/badger/kv_test.go
+++ b/badger/kv_test.go
@@ -667,6 +667,39 @@ func TestDirNotExists(t *testing.T) {
 	require.Error(t, err)
 }
 
+func TestDeleteWithoutSyncWrite(t *testing.T) {
+	dir, err := ioutil.TempDir("/tmp", "badger")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+	opt := new(Options)
+	*opt = DefaultOptions
+	opt.Dir = dir
+	opt.ValueDir = dir
+	kv, err := NewKV(opt)
+	if err != nil {
+		t.Error(err)
+		t.Fail()
+	}
+
+	key := []byte("k1")
+	// Set a value with size > value threshold so that its written to value log.
+	require.NoError(t, kv.Set(key, []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789FOOBARZOGZOG")))
+	require.NoError(t, kv.Delete(key))
+	kv.Close()
+
+	// Reopen KV
+	kv, err = NewKV(opt)
+	if err != nil {
+		t.Error(err)
+		t.Fail()
+	}
+	defer kv.Close()
+
+	item := KVItem{}
+	require.NoError(t, kv.Get(key, &item))
+	require.Equal(t, 0, len(item.Value()))
+}
+
 func BenchmarkExists(b *testing.B) {
 	dir, err := ioutil.TempDir("/tmp", "badger")
 	require.NoError(b, err)
diff --git a/badger/value.go b/badger/value.go
index 590d5a4cdf7..c80994826ac 100644
--- a/badger/value.go
+++ b/badger/value.go
@@ -659,7 +659,7 @@ func (l *valueLog) write(reqs []*request) error {
 			y.AssertTruef(e.Meta&BitCompressed == 0, "Cannot set BitCompressed outside valueLog")
 			var p valuePointer
 
-			if !l.opt.SyncWrites && len(e.Value) < l.opt.ValueThreshold {
+			if !l.opt.SyncWrites && (e.Meta != BitDelete) && len(e.Value) < l.opt.ValueThreshold {
 				// No need to write to value log.
 				b.Ptrs = append(b.Ptrs, p)
 				continue